Traffic conflict techniques for safety and operations: engineers guide

Abstract

This guide provides basic background information and standard procedures for using traffic conflicts to analyze safety and operational problems at signalized and unsignalized intersections. The guide was prepared for engineers and supervisors who have the responsibility for analyzing conflict data and using the results to make decisions and recommendations for improvements. Based on previous research and experiences, the procedures described in this guide provide a standard, cost effective method for using traffic conflicts to diagnose safety and operational problems at intersections. The guide contains definitions with illustrations and examples of conflict types, step by step procedures for conducting a conflict study, methods for analyzing and interpreting the data, and guidelines for using conflict data to select countermeasures. Because the reliability of conflict data is dependent upon the ability of the observers to record conflicts accurately, a section of the guide is devoted to training data collectors. Also available, as a training aid and reference source, is an observer's manual (FHWA-IP-88-027) (A).